Unless you are a professional watchmaker, you never have the chance to see how your expensive GMT watch at work. Its moving oscillator, the energetic hairspring & balance wheel , the ticking of the fork etc. When you replace our sapphire crystal display watch back which is custom made for the GMT models, the entire escapement system where the aesthetics and technology in action, is visible to you. We ship all my items to worldwide standard int mail by avia. Delivery time to USA is 10-15 days. Europe 11-25 days. We ship within 2-3 business days. Your watch will be shipped in soft safety box! We hope you will love your purchase, however if you need to return it, we have a 60 day return policy. We hope you will love your purchase, however if you need to return it, we have a 60 day return po.